Adding hourly- (time-)maximum composite reflectivity to output

[Jeff_Duda]

I want to add a time-maximum composite reflectivity to be output from MPAS...specifically for the TEMPO microphysics. I see that 3D reflectivity is already calculated in the microphysics driver, and there's even a subroutine for calculating the hourly max values of 1-km AGL reflectivity. However, when I modified the code to track a max composite reflectivity value, the new field in the diag files is identical to the composite reflectivity that is already calculated by the existing code.

As a quick aside, I recently modified the MPAS code to output hourly-max precipitation rate and that product looks like what I expected, so I think I was successful in making the code changes for that particular field. So I have been trying to model the changes I made for the maximum precipitation rate for the maximum of composite reflectivity. But the two fields have a different trajectory through the model code:

• Precipitation rate can be directly derived from the rainncv variable which is calculated directly in the microphysics scheme subroutines (a level below the driver). Once back in the microphysics_driver, rainncv is not modified.
• On the other hand, 3D reflectivity is calculated in the individual microphysics scheme subroutines, but the computation to calculate the vertical max is performed in a separate subroutine towards the end of the driver code.

I noted the use of a

[var_name]_p

nomenclature for a lot of microphysics scheme variables. These are declared in mpas_atmphys_vars.F and presumably allow for certain arrays to be tracked outside of the individual microphysics scheme subroutines. So I do have this declared for the maximum composite reflectivity by tracking just the composite reflectivity through time in mpas_atmphys_vars.F:

 real(kind=RKIND),dimension(:,:),allocatable:: &
    refl10cm_1km_p, &
    refl10cm_max_p

This section at the end of the microphysics driver is where I could use the most help in understanding:

 !ensure that we only call compute_radar_reflectivity() if we are using an MPS that supports
 !the computation of simulated radar reflectivity:
 if (l_diags) then
    if(trim(microp_scheme) == "mp_wsm6"     .or. &
       trim(microp_scheme) == "mp_thompson" .or. &
       trim(microp_scheme) == "mp_thompson_aerosols" .or. &
       trim(microp_scheme) == "mp_tempo" .or. &
       trim(microp_scheme) == "mp_nssl2m"   ) then
!       call mpas_log_write('Computing 3d reflectivity')
       call compute_radar_reflectivity(configs,diag_physics,its,ite)
    else
       call mpas_log_write('*** NOTICE: NOT computing simulated radar reflectivity')
       call mpas_log_write('            since WSM6 or Thompson microphysics scheme was not selected')
    end if

    !calculate the relative humidity over water if the temperature is strictly greater than 0.C,
    !over ice otherwise.
    call compute_relhum(diag,its,ite)

 end if

 if (do_diag_dbz_flag) then
    if(trim(microp_scheme) == "mp_tempo"    .or. &
       trim(microp_scheme) == "mp_nssl2m"   ) then
       call mpas_log_write('Computing hourly max reflectivity')
       call compute_hourly_max_radar_reflectivity(configs,diag_physics,its,ite)
    else
       call mpas_log_write('*** NOTICE: NOT computing hourly max simulated radar reflectivity')
       call mpas_log_write('            since WSM6 or Thompson microphysics scheme was not selected')
    end if
 endif

 if(trim(microp_scheme) == "mp_tempo") then
    call mpas_log_write('Computing accumulated max hail diameter at the surface')
    call compute_accumulated_max_hail(diag_physics,its,ite)
 endif

!... copy updated precipitation from the wrf-physics grid back to the geodesic-dynamics grid:
 call precip_to_MPAS(configs,diag_physics,its,ite)

!... copy updated cloud microphysics variables from the wrf-physics grid back to the geodesic-
!    dynamics grid:
 call microphysics_to_MPAS(configs,mesh,state,time_lev,diag,diag_physics,tend_physics,tend,its,ite)

From comments higher up in the driver source code file it seems like the "whatever_to_MPAS" subroutines covert the local variables to variables that the higher-level MPAS code needs to output them in the history files. There is one for precip and one for microphysics. The crux of my code additions is this:

                max_compref(i) = max(max_compref(i),refl10cm_max_p(i,j))

The uncertainty in my code then is where to place this command. For the hourly-max precipitation rate it is located in the precip_to_MPAS subroutine:

    !time-step precipitation:
    rainncv(i) = rainnc_p(i,j)
    prate_max(i) = max(rainnc_p(i,j)/dt_microp,prate_max(i))

...and that seems to be working. But putting the analogous line in microphysics_to_MPAS (in a select-case statement for 'mp_tempo') is resulting in that field looking the same as composite reflectivity. So I don't know what I'm missing and could use some help. Thanks.

 

[Ming Chen]

Hi Jeff,

Thank you for the detailed explanation of your issue. We will look into the problem and get back to you. It may take some time and thank you for your patience.

 

[Ming Chen]

Jeff,

Would you please tell me which version of MPAS you are working on? It seems that the code you are modifying is not from an officially released version of MPAS. Please let me know if I am wrong.

Please send me the original code and the modified code. I would like to get a complete picture of what you have modified.

Thanks.